audit_init() was not declared in header, causing warnings; fix this and namespace it

audit_init() was not declared in header, causing warnings; fix this and namespace it

2007-10-23  Havoc Pennington  <hp@redhat.com>

	* bus/bus.c (bus_context_new): use the new name here

	* bus/selinux.c (bus_selinux_audit_init): rename from audit_init()
	to avoid possible libc conflict, and declare it in .h file to
	avoid a warning